John Wesley on Leviticus 15:31

When they defile my tabernacle - Both ceremonially, by coming into it in their uncleanness, and morally by the contempt of God's express command to cleanse themselves. The grand reason of all these laws was, to separate the children of Israel from their uncleanness. Hereby they were taught their privilege and honour, that they were purified unto God, a peculiar people; for that was a defilement to them, which was not so to others. They were also taught their duty, which was to keep themselves clean from all pollutions.